US20220373715A1

US20220373715A1 - Plastic light-folding element, imaging lens assembly module and electronic device

Info

Publication number: US20220373715A1
Application number: US17/711,168
Authority: US
Inventors: Wen-Yu Tsai; Chien-Pang Chang; Ming-Ta Chou; Kuo-Chiang Chu
Original assignee: Largan Precision Co Ltd
Current assignee: Largan Precision Co Ltd
Priority date: 2021-05-21
Filing date: 2022-04-01
Publication date: 2022-11-24
Also published as: CN115390168A; EP4092455A1; CN216210000U

Abstract

A plastic light-folding element includes an incident surface, an exit surface, a reflective surface and a reflective optical layer. The incident surface and the exit surface are configured to lead an imaging light enter and exit the plastic light-folding element, respectively. The reflective surface is configured to fold the imaging light. The reflective optical layer is disposed on the reflective surface, and includes an Ag layer, a bottom layer optical film and a top layer optical film. The bottom layer optical film is contacted with the Ag layer, and the bottom layer optical film is closer to the reflective surface than the Ag layer to the reflective surface. A refractive index of the top layer optical film is lower than a refractive index of the bottom layer optical film, and the top layer optical film is not contacted with the Ag layer.

Description

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Ser. No. 63/191,366, filed May 21, 2021 and Taiwan Application Serial Number 110130558, filed Aug. 18, 2021, which are herein incorporated by reference.

BACKGROUND

Technical Field

The present disclosure relates to a plastic light-folding element and an imaging lens assembly module. More particularly, the present disclosure relates to a plastic light-folding element and an imaging lens assembly module applicable to portable electronic devices.

Description of Related Art

In recent years, portable electronic devices have developed rapidly. For example, intelligent electronic devices and tablets have been filled in the lives of modern people, and imaging lens assembly modules and plastic light-folding elements thereof mounted on portable electronic devices have also prospered. However, as technology advances, the quality requirements of the plastic light-folding elements are becoming higher and higher. Therefore, a plastic light-folding element, which can enhance the degree of the image restoration, needs to be developed.

SUMMARY

According to one aspect of the present disclosure, a plastic light-folding element includes an incident surface, an exit surface, a reflective surface and a reflective optical layer. The incident surface is configured to lead an imaging light enter the plastic light-folding element. The exit surface is configured to lead the imaging light exit the plastic light-folding element. The reflective surface is configured to fold the imaging light. The reflective optical layer is disposed on a surface of the reflective surface. The reflective optical layer includes an Ag layer, a bottom layer optical film and a top layer optical film. The Ag layer is configured to lead the imaging light, which enters the incident surface, reflect to the exit surface. The bottom layer optical film is directly contacted with the Ag layer, and the bottom layer optical film is closer to the reflective surface of the plastic light-folding element than the Ag layer to the reflective surface of the plastic light-folding element. A refractive index of the top layer optical film is lower than a refractive index of the bottom layer optical film, wherein the top layer optical film is not directly contacted with the Ag layer, and the top layer optical film is farther from the reflective surface of the plastic light-folding element than the Ag layer from the reflective surface of the plastic light-folding element. When the refractive index of the bottom layer optical film is Nb, a thickness of the bottom layer optical film is db, the refractive index of the top layer optical film is Nt, a thickness of the top layer optical film is dt, a thickness of the Ag layer is dAg, and the following conditions are satisfied: 1.4<Nt<Nb<2.1; 1.6<Nb<2.1; 1.4<Nt<1.58; 0.05<db/dAg<1.2; and 0.2<dAg/dt<3.5.
According to one aspect of the present disclosure, an imaging lens assembly module includes the plastic light-folding element of the aforementioned aspect and an optical imaging lens assembly, wherein the plastic light-folding element is disposed on one of an object side and an image side of the optical imaging lens assembly.
According to one aspect of the present disclosure, an electronic device includes the imaging lens assembly module of the aforementioned aspect and an image sensor, wherein the image sensor is disposed on an image surface of the imaging lens assembly module.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a three dimensional view of an electronic device according to the 1st example of the present disclosure.

FIG. 1B is an exploded view of the electronic device according to the 1st example in FIG. 1A.

FIG. 1C is another exploded view of the electronic device according to the 1st example in FIG. 1A.

FIG. 1D is a schematic view of the electronic device according to the 1st example in FIG. 1A.

FIG. 1E is a schematic view of the plastic light-folding element according to the 1st example in FIG. 1A.

FIG. 1F is a schematic view of a reflectivity result according to the 1st example in FIG. 1A.

FIG. 2 is a schematic view of an electronic device according to the 2nd example of the present disclosure.

FIG. 3A is a schematic view of an electronic device according to the 3rd example of the present disclosure.

FIG. 3B is a three dimensional view of the plastic light-folding element according to the 3rd example in FIG. 3A.

FIG. 3C is another three dimensional view of the plastic light-folding element according to the 3rd example in FIG. 3A.

FIG. 3D is a schematic view of an incident surface and a reflective surface of the plastic light-folding element according to the 3rd example in FIG. 3A.

FIG. 4A is a schematic view of an electronic device according to the 4th example of the present disclosure.

FIG. 4B is another schematic view of the electronic device according to the 4th example in FIG. 4A.

FIG. 4C is a schematic view of an image according to the 4th example in FIG. 4A.

FIG. 4D is another schematic view of an image according to the 4th example in FIG. 4A.

FIG. 4E is still another schematic view of an image according to the 4th example in FIG. 4A.

FIG. 5 is a schematic view of an electronic device according to the 5th example of the present disclosure.

DETAILED DESCRIPTION

The present disclosure provides a plastic light-folding element, and the plastic light-folding element includes an incident surface, an exit surface, a reflective surface and a reflective optical layer. The incident surface is configured to lead an imaging light enter the plastic light-folding element. The exit surface is configured to lead the imaging light exit the plastic light-folding element. The reflective surface is configured to fold the imaging light. The reflective optical layer is disposed on a surface of the reflective surface, and the reflective optical layer includes an Ag layer, a bottom layer optical film and a top layer optical film. The Ag layer is configured to lead the imaging light, which enters the incident surface, reflect to the exit surface. The bottom layer optical film is directly contacted with the Ag layer, and the bottom layer optical film is closer to the reflective surface of the plastic light-folding element than the Ag layer to the reflective surface of the plastic light-folding element. A refractive index of the top layer optical film is lower than a refractive index of the bottom layer optical film, wherein the top layer optical film is not directly contacted with the Ag layer, and the top layer optical film is farther from the reflective surface of the plastic light-folding element than the Ag layer from the reflective surface of the plastic light-folding element. When the refractive index of the bottom layer optical film is Nb, a thickness of the bottom layer optical film is db, the refractive index of the top layer optical film is Nt, a thickness of the top layer optical film is dt, and a thickness of the Ag layer is dAg, the following conditions are satisfied: 1.4<Nt<Nb<2.1; 1.6<Nb<2.1; 1.4<Nt<1.58; 0.05<db/dAg<1.2; and 0.2<dAg/dt<3.5.
In particular, the plastic light-folding element of the present disclosure is an optical element disposing the Ag layer on the reflective surface made of a plastic material for folding the imaging light. The physical adhesion between the Ag layer and the reflective surface made of the plastic material is enhanced via the bottom layer optical film, and the higher refractive index can be maintained via the bottom layer optical film so as to reduce the unnecessary reflection inside the plastic light-folding element to increase the image restoration of the imaging light.
The plastic light-folding element can further include a connecting surface and a gate vestige structure. The connecting surface is connected to the incident surface, the exit surface and the reflective surface. The gate vestige structure is disposed on the connecting surface. The injecting efficiency of the injection molding can be enhanced by disposing the gate vestige structure on the connecting surface, and the better optical flatness and the better circular symmetry consistency of the incident surface, the exit surface and the reflective surface can be obtained by simultaneously forming the incident surface, the exit surface and the reflective surface.
The bottom layer optical film can be a metal oxide layer. In particular, the metal oxide layer includes a metal material, the stronger binding force between the metal oxide layer and the Ag layer and the stronger binding force between the metal oxide layer and the plastic material can be simultaneously obtained, and hence the binding force between the bottom layer optical film made of the metal oxide and the metal material is higher than the binding force between the bottom layer optical film made of the non-metal oxide and the metal material. In other words, the better adhesion of the Ag layer to the plastic material can be obtained via the metal oxide layer. It should be mentioned that an ordinary adhesive test is to stick the tape on a surface of the optical layer and then tear off the tape to check the surface condition of the optical layer, and the quality of the adhesion is determined via the surface condition of the optical layer, wherein the more serious test condition can be obtained by increasing the numbers of sticking and tearing off the tape, but the present disclosure is not limited thereto. In particular, the bottom layer optical film can be made of Al₂O₃, the top layer optical film can be made of a non-metal oxide, such as SiO₂.
The plastic light-folding element can further include at least one intermediate layer, wherein the intermediate layer is disposed between the top layer optical film and the Ag layer. Via the intermediate layer, the Ag layer can be protected so that the Ag layer is not easily oxidized, and the ability of the resistant to the corrosion of acid and alkali of the Ag layer can be enhanced, but the effect of the intermediate layer is not limited thereto.
The intermediate layer can include a metal layer excluding a silver atom. In particular, the material of the metal layer can be Ti, Cr, Ni and so on, but the present disclosure is not limited thereto. The surface stability of the Ag layer can be enhanced via the metal layer excluding the silver atom so that the Ag layer is not easily influenced by the external environment, and the combination between the Ag layer and the metal layer excluding the silver atom is better.
The bottom layer optical film can be directly contacted with the reflective surface of the plastic light-folding element. Therefore, the degree of the optical reflection of the Ag layer can be enhanced to maintain the higher optical reflectivity. In particular, the degree of the optical reflection of the silver atom is better than the degree of the optical reflection of the aluminum atom, and the reflecting effect of the Ag layer can be not easily influenced and decreased via the plastic material by disposing the bottom layer optical film.
When the thickness of the Ag layer is dAg, the following condition can be satisfied: 75 nm<dAg<200 nm. The reflecting effect of the imaging light can be better via the Ag layer with the proper thickness, and the degree of the reflection of the light wavelengths of the different imaging light bands can be more consistent. Therefore, the better degree of the restored image of the imaging light can be obtained, and the reflecting image can be more delicate, more realistic and gentler. It should be mentioned that the inconsistent thickness of the Ag layer with the excessively thick is easily obtained so that the distortion of the reflecting image is caused.
When the thickness of the bottom layer optical film is db, and the thickness of the top layer optical film is dt, the following condition can be satisfied: 0.05<db/dt<1.1. The better optical characteristic of the plastic light-folding element can be obtained by the thinner bottom layer optical film. In particular, the optical characteristic can be the color rendering of the image light, the restoring degree of the image light or the detail of the image light, but the present disclosure is not limited thereto.
When a lowest reflectivity of a reflectivity of the reflective optical layer between wavelengths of 540 nm to 590 nm is R5459, the following condition can be satisfied: 94.0%<R5459<99.99%. By the high reflectivity of the visible light band, the authenticity of the image can be faithfully presented, and the addition loss of the original light by the plastic light-folding element can be reduced to enhance the imaging quality.
Each of the aforementioned features of the plastic light-folding element can be utilized in various combinations for achieving the corresponding effects.
The present disclosure provides an imaging lens assembly module, which includes the aforementioned plastic light-folding element and an optical imaging lens assembly, wherein the plastic light-folding element is disposed on one of an object side and an image side of the optical imaging lens assembly. In particular, the imaging lens assembly module can be applied to the telephoto (that is, the full view is less than 40 degrees) by the disposition of the plastic light-folding element. Therefore, the volume of the imaging lens assembly module can be effectively reduced.
The present disclosure provides an electronic device, which includes the aforementioned imaging lens assembly module and an image sensor, wherein the image sensor is disposed on an image surface of the imaging lens assembly module.
According to the aforementioned embodiment, specific examples are provided, and illustrated via figures.
<1st Example>
FIG. 1A is a three dimensional view of an electronic device 10 according to the 1st example of the present disclosure. FIG. 1B is an exploded view of the electronic device 10 according to the 1st example in FIG. 1A. FIG. 1C is another exploded view of the electronic device 10 according to the 1st example in FIG. 1A. FIG. 1D is a schematic view of the electronic device 10 according to the 1st example in FIG. 1A. In FIGS. 1A to 1D, the electronic device 10 includes an imaging lens assembly module (its reference numeral is omitted) and an image sensor 180, wherein the image sensor 180 is disposed on an image surface (its reference numeral is omitted) of the imaging lens assembly module.
Moreover, the electronic device 10 further includes a cover 150, a first driving apparatus (its reference numeral is omitted), a second driving apparatus (its reference numeral is omitted), a carrier 160 and a flexible circuit board 170, wherein the first driving apparatus includes a first driving member 131, first magnets 132, first rolling members 133, magnetic members 134 and first coils 135, and the second driving apparatus includes a second driving member 141, second magnets 142, a second rolling member 143, an elastic member 144 and second coils 145. In particular, the first driving apparatus and the second driving apparatus are configured to drive the imaging lens assembly module, the imaging lens assembly module is disposed in the carrier 160, the flexible circuit board 170 is disposed on a surface of the carrier 160, and the cover 150 is disposed on another surface of the carrier 160.
The imaging lens assembly module includes a plastic light-folding element 110 and an optical imaging lens assembly (its reference numeral is omitted), wherein the plastic light-folding element 110 is disposed an object side of the optical imaging lens assembly. In particular, the imaging lens assembly module can be applied to the telephoto (that is, the full view is less than 40 degrees) by the disposition of the plastic light-folding element 110. Therefore, the volume of the imaging lens assembly module can be effectively reduced.
In FIG. 1D, the optical imaging lens assembly, in order from the object side to an image side, includes lens elements 121 a, 121 b, 121 c, 121 d and a retainer 123, and the lens elements 121 a, 121 b, 121 c are disposed in a lens barrel 122 of the optical imaging lens assembly, and the lens element 121 d and the retainer 123 are disposed in the first driving member 131, wherein the optical features such as numbers, structures, surface shapes and so on of the lens elements can be disposed according to different imaging demand, and the optical features are not limited thereto.
FIG. 1E is a schematic view of the plastic light-folding element 110 according to the 1st example in FIG. 1A. In FIGS. 1A to 1E, the plastic light-folding element 110 includes an incident surface 111, an exit surface 112, a reflective surface 113 and a reflective optical layer 114. In detail, the incident surface 111 is configured to lead an imaging light (its reference numeral is omitted) enter the plastic light-folding element 110, the exit surface 112 is configured to lead the imaging light exit the plastic light-folding element 110, the reflective surface 113 is configured to fold the imaging light, and the reflective optical layer 114 is disposed on a surface of the reflective surface 113. According to the 1st example, the plastic light-folding element 110 can be a plastic lens element, and the incident surface 111 has an optical curved surface, but the present disclosure is not limited thereto.
The reflective optical layer 114 includes an Ag layer 114 a, a bottom layer optical film 114 b and a top layer optical film 114 c, wherein the Ag layer 114 a is configured to lead the imaging light, which enters the incident surface 111, reflect to the exit surface 112; the bottom layer optical film 114 b is directly contacted with the Ag layer 114 a, and the bottom layer optical film 114 b is closer to the reflective surface 113 of the plastic light-folding element 110 than the Ag layer 114 a to the reflective surface 113 of the plastic light-folding element 110; a refractive index of the top layer optical film 114 c is lower than a refractive index of the bottom layer optical film 114 b, wherein the top layer optical film 114 c is not directly contacted with the Ag layer 114 a, and the top layer optical film 114 c is farther from the reflective surface 113 of the plastic light-folding element 110 than the Ag layer 114 a from the reflective surface 113 of the plastic light-folding element 110.
In particular, the plastic light-folding element 110 is an optical element disposing the Ag layer 114 a on the reflective surface 113 made of the plastic material for folding the imaging light. The physical adhesion between the Ag layer 114 a and the reflective surface 113 made of the plastic material is enhanced via the bottom layer optical film 114 b, and the higher refractive index can be maintained via the bottom layer optical film 114 b so as to reduce the unnecessary reflection inside the plastic light-folding element 110 to increase the image restoration of the imaging light.
In FIGS. 1B and 1E, the plastic light-folding element 110 can further include at least one connecting surface 115, a gate vestige structure 116 and at least one intermediate layer 117. The connecting surface 115 is connected to the incident surface 111, the exit surface 112 and the reflective surface 113. The gate vestige structure 116 is disposed on the connecting surface 115. The intermediate layer 117 is disposed between the top layer optical film 114 c and the Ag layer 114 a. The injecting efficiency of the injection molding can be enhanced by disposing the gate vestige structure 116 on the connecting surface 115, and the better optical flatness and the better circular symmetry consistency of the incident surface 111, the exit surface 112 and the reflective surface 113 can be obtained by simultaneously forming the incident surface 111, the exit surface 112 and the reflective surface 113. Furthermore, via the intermediate layer 117, the Ag layer 114 a can be protected so that the Ag layer 114 a is not easily oxidized, and the ability of the resistant to the corrosion of acid and alkali of the Ag layer 114 a can be enhanced, but the effect of the intermediate layer 117 is not limited thereto. According to the 1st example, a number of the connecting surface 115 is two, a number of the gate vestige structure 116 is one, and a number of the intermediate layer 117 is two.
It should be mentioned that the drawing number of the intermediate layer 117 is one, but the real number of the intermediate layer 117 can be two or more, and the present disclosure is not limited thereto.
The bottom layer optical film 114 b is a metal oxide layer. In particular, the metal oxide layer includes a metal material, the stronger binding force between the metal oxide layer and the Ag layer 114 a and the stronger binding force between the metal oxide layer and the plastic material can be simultaneously obtained, and hence the binding force between the bottom layer optical film 114 b made of the metal oxide and the metal material is higher than the binding force between the bottom layer optical film made of the non-metal oxide and the metal material. In other words, the better adhesion of the Ag layer 114 a to the plastic material can be obtained via the metal oxide layer. It should be mentioned that an ordinary adhesive test is to stick the tape on a surface of the optical layer and then tear off the tape to check the surface condition of the optical layer, and the quality of the adhesion is determined via the surface condition of the optical layer, wherein the serious test condition can be obtained by increasing the numbers of sticking and tearing off the tape, but the present disclosure is not limited thereto. According to the 1st example, the bottom layer optical film 114 b is made of Al₂O₃, and the top layer optical film 114 c is made of SiO₂.
Each of the intermediate layers 117 includes a metal layer excluding a silver atom. The surface stability of the Ag layer can be enhanced via the metal layer excluding the silver atom so that the Ag layer is not easily influenced by the external environment, and the combination between the Ag layer and the metal layer excluding the silver atom is better. In particular, the material of the metal layer can be Ti, Cr, Ni and so on, but the present disclosure is not limited thereto.
The bottom layer optical film 114 b is directly contacted with the reflective surface 113 of the plastic light-folding element 110. Therefore, the degree of the optical reflection of the Ag layer 114 a can be enhanced to maintain the higher optical reflectivity. In particular, the degree of the optical reflection of the silver atom is better than the degree of the optical reflection of the aluminum atom, and the reflecting effect of the Ag layer 114 a can be not easily influenced and decreased via the plastic material by disposing the bottom layer optical film 114 b.
When the refractive index of the bottom layer optical film 114 b is Nb, a thickness of the bottom layer optical film 114 b is db, the refractive index of the top layer optical film 114 c is Nt, a thickness of the top layer optical film 114 c is dt, a refractive index of the Ag layer 114 a is NAg, and a thickness of the Ag layer 114 a is dAg, the following conditions of the Table 1 are satisfied.

TABLE 1

1st example

Nb	1.6726	db (nm)	20
Nt	1.4618	dt (nm)	65
NAg	0.051	dAg (nm)	100

It should be mentioned that the refractive index of the air is 1, the refractive index of the plastic light-folding element 110 is 1.64678, and a thickness of each of the intermediate layers 117 is less than the thickness of the Ag layer 114 a.
FIG. 1F is a schematic view of a reflectivity result according to the 1st example in FIG. 1A. Table 2 is a reflectivity result according to the 1st example.

	TABLE 2

	wavelength (nm)	reflectivity (%)

	380	92.88095
	381	92.86194
	382	92.84323
	383	92.82481
	384	92.80669
	385	92.78886
	386	92.77169
	387	92.75479
	388	92.73817
	389	92.72181
	390	92.70572
	391	92.6899
	392	92.67434
	393	92.65904
	394	92.64399
	395	92.6292
	396	92.61466
	397	92.60037
	398	92.58631
	399	92.57251
	400	92.55895
	401	92.6218
	402	92.71196
	403	92.79902
	404	92.86623
	405	92.92973
	406	93.01429
	407	93.08696
	408	93.15476
	409	93.22368
	410	93.29611
	411	93.37138
	412	93.43712
	413	93.51066
	414	93.57662
	415	93.64599
	416	93.71353
	417	93.78017
	418	93.84982
	419	93.91608
	420	93.98196
	421	94.05391
	422	94.11569
	423	94.17811
	424	94.24311
	425	94.30622
	426	94.37049
	427	94.43313
	428	94.49608
	429	94.55893
	430	94.61788
	431	94.68102
	432	94.74079
	433	94.79897
	434	94.86155
	435	94.91983
	436	94.97828
	437	95.03615
	438	95.09356
	439	95.15109
	440	95.20763
	441	95.26249
	442	95.32109
	443	95.37639
	444	95.43024
	445	95.48506
	446	95.54042
	447	95.59198
	448	95.64536
	449	95.69852
	450	95.75127
	451	95.77848
	452	95.80676
	453	95.83338
	454	95.86246
	455	95.88948
	456	95.91631
	457	95.94362
	458	95.96984
	459	95.9968
	460	96.02327
	461	96.04878
	462	96.07622
	463	96.10215
	464	96.12655
	465	96.15248
	466	96.17751
	467	96.20257
	468	96.22835
	469	96.25341
	470	96.27808
	471	96.30277
	472	96.32669
	473	96.35085
	474	96.37608
	475	96.3987
	476	96.4226
	477	96.44644
	478	96.46936
	479	96.4925
	480	96.51593
	481	96.53862
	482	96.56162
	483	96.58405
	484	96.60665
	485	96.62932
	486	96.65138
	487	96.67279
	488	96.69484
	489	96.71672
	490	96.73787
	491	96.75943
	492	96.78084
	493	96.80189
	494	96.82331
	495	96.84414
	496	96.86485
	497	96.88529
	498	96.9058
	499	96.92585
	500	96.94614
	501	96.95403
	502	96.96276
	503	96.97102
	504	96.97887
	505	96.987
	506	96.99552
	507	97.00351
	508	97.01161
	509	97.01959
	510	97.02776
	511	97.03577
	512	97.0435
	513	97.05177
	514	97.05945
	515	97.06723
	516	97.07502
	517	97.08307
	518	97.09087
	519	97.09856
	520	97.10637
	521	97.11406
	522	97.12172
	523	97.12935
	524	97.13686
	525	97.14451
	526	97.15197
	527	97.15956
	528	97.16702
	529	97.1744
	530	97.18201
	531	97.18959
	532	97.19693
	533	97.20424
	534	97.21165
	535	97.21893
	536	97.22616
	537	97.23347
	538	97.24069
	539	97.24789
	540	97.25507
	541	97.26222
	542	97.26933
	543	97.27646
	544	97.28353
	545	97.29051
	546	97.29762
	547	97.30452
	548	97.31151
	549	97.3185
	550	97.32532
	551	97.3317
	552	97.33801
	553	97.34424
	554	97.35054
	555	97.35677
	556	97.36297
	557	97.3692
	558	97.37532
	559	97.3815
	560	97.38758
	561	97.39369
	562	97.39979
	563	97.40586
	564	97.41191
	565	97.41795
	566	97.42395
	567	97.42994
	568	97.43589
	569	97.44183
	570	97.44776
	571	97.45365
	572	97.45954
	573	97.4654
	574	97.47123
	575	97.47704
	576	97.48284
	577	97.48861
	578	97.49437
	579	97.50011
	580	97.50582
	581	97.51151
	582	97.51718
	583	97.52284
	584	97.52848
	585	97.53409
	586	97.53969
	587	97.54527
	588	97.55082
	589	97.55638
	590	97.56187
	591	97.56738
	592	97.57285
	593	97.57832
	594	97.58374
	595	97.58918
	596	97.59457
	597	97.59995
	598	97.60531
	599	97.61067
	600	97.61598
	601	97.61791
	602	97.61987
	603	97.62181
	604	97.62378
	605	97.62574
	606	97.62776
	607	97.62964
	608	97.63166
	609	97.63365
	610	97.63568
	611	97.6377
	612	97.63972
	613	97.64172
	614	97.64372
	615	97.64581
	616	97.64788
	617	97.64988
	618	97.65198
	619	97.65404
	620	97.65608
	621	97.6582
	622	97.66026
	623	97.66242
	624	97.66447
	625	97.6665
	626	97.66864
	627	97.67075
	628	97.67282
	629	97.67486
	630	97.67703
	631	97.67912
	632	97.68129
	633	97.68341
	634	97.68553
	635	97.68773
	636	97.6898
	637	97.69189
	638	97.69413
	639	97.69624
	640	97.69838
	641	97.70052
	642	97.70271
	643	97.70492
	644	97.70698
	645	97.70915
	646	97.71131
	647	97.71355
	648	97.71569
	649	97.71783
	650	97.7201
	651	97.7248
	652	97.72953
	653	97.73418
	654	97.73895
	655	97.74347
	656	97.74824
	657	97.75285
	658	97.75745
	659	97.76207
	660	97.76665
	661	97.77129
	662	97.77568
	663	97.78039
	664	97.78488
	665	97.78938
	666	97.79385
	667	97.79835
	668	97.80278
	669	97.80724
	670	97.81164
	671	97.81608
	672	97.82047
	673	97.82499
	674	97.82919
	675	97.83356
	676	97.83794
	677	97.84223
	678	97.84665
	679	97.8509
	680	97.85517
	681	97.85935
	682	97.86372
	683	97.86791
	684	97.87209
	685	97.87644
	686	97.88042
	687	97.88473
	688	97.88885
	689	97.89285
	690	97.89718
	691	97.90112
	692	97.90534
	693	97.90941
	694	97.91344
	695	97.91744
	696	97.92157
	697	97.92559
	698	97.92974
	699	97.93355
	700	97.9375
	701	97.94164
	702	97.94578
	703	97.94993
	704	97.95395
	705	97.95823
	706	97.96229
	707	97.96615
	708	97.97025
	709	97.97426
	710	97.97814
	711	97.98222
	712	97.98633
	713	97.99027
	714	97.99426
	715	97.99808
	716	98.00194
	717	98.00593
	718	98.00982
	719	98.01382
	720	98.01767
	721	98.02146
	722	98.0254
	723	98.02911
	724	98.03285
	725	98.03685
	726	98.04048
	727	98.04435
	728	98.04789
	729	98.05155
	730	98.05551
	731	98.05912
	732	98.0628
	733	98.06649
	734	98.07038
	735	98.07401
	736	98.07774
	737	98.08132
	738	98.0849
	739	98.08864
	740	98.09204
	741	98.09587
	742	98.09918
	743	98.10295
	744	98.10648
	745	98.10989
	746	98.11354
	747	98.11677
	748	98.12041
	749	98.12405
	750	98.12733
	751	98.1283
	752	98.12883
	753	98.12947
	754	98.13053
	755	98.13129
	756	98.13211
	757	98.13278
	758	98.13417
	759	98.13471
	760	98.13531
	761	98.13634
	762	98.13677
	763	98.13797
	764	98.13857
	765	98.13929
	766	98.14027
	767	98.14106
	768	98.14193
	769	98.14279
	770	98.14357
	771	98.14444
	772	98.14547
	773	98.14606
	774	98.14698
	775	98.14778
	776	98.14869
	777	98.14976
	778	98.15024
	779	98.15114
	780	98.15214
	781	98.15301
	782	98.15388
	783	98.15475
	784	98.15563
	785	98.15651
	786	98.15739
	787	98.15827
	788	98.15916
	789	98.16005
	790	98.16094
	791	98.16184
	792	98.16273
	793	98.16363
	794	98.16454
	795	98.16544
	796	98.16635
	797	98.16726
	798	98.16817
	799	98.16908
	800	98.17
	801	98.17092
	802	98.17184
	803	98.17276
	804	98.17369
	805	98.17461
	806	98.17554
	807	98.17647
	808	98.17741
	809	98.17834
	810	98.17928
	811	98.18022
	812	98.18116
	813	98.18211
	814	98.18305
	815	98.184
	816	98.18495
	817	98.18589
	818	98.18684
	819	98.1878
	820	98.18875
	821	98.1897
	822	98.19066
	823	98.19162
	824	98.19258
	825	98.19354
	826	98.19451
	827	98.19547
	828	98.19644
	829	98.1974
	830	98.19837
	831	98.19935
	832	98.20032
	833	98.20129
	834	98.20227
	835	98.20324
	836	98.20422
	837	98.2052
	838	98.20618
	839	98.20716
	840	98.20815
	841	98.20913
	842	98.21012
	843	98.21111
	844	98.21209
	845	98.21308
	846	98.21408
	847	98.21507
	848	98.21606
	849	98.21706
	850	98.21805
	851	98.22043
	852	98.22281
	853	98.22518
	854	98.22754
	855	98.2299
	856	98.23225
	857	98.2346
	858	98.23694
	859	98.23927
	860	98.2416
	861	98.24393
	862	98.24624
	863	98.24855
	864	98.25085
	865	98.25315
	866	98.25545
	867	98.25773
	868	98.26001
	869	98.26229
	870	98.26456
	871	98.26683
	872	98.26908
	873	98.27134
	874	98.27359
	875	98.27583
	876	98.27807
	877	98.2803
	878	98.28252
	879	98.28474
	880	98.28696
	881	98.28917
	882	98.29137
	883	98.29357
	884	98.29577
	885	98.29796
	886	98.30014
	887	98.30232
	888	98.30449
	889	98.30666
	890	98.30882
	891	98.31098
	892	98.31313
	893	98.31527
	894	98.31742
	895	98.31955
	896	98.32168
	897	98.32381
	898	98.32593
	899	98.32805
	900	98.33016
	901	98.33195
	902	98.33374
	903	98.33552
	904	98.3373
	905	98.33908
	906	98.34085
	907	98.34262
	908	98.34438
	909	98.34614
	910	98.3479
	911	98.34965
	912	98.35141
	913	98.35315
	914	98.3549
	915	98.35664
	916	98.35837
	917	98.36011
	918	98.36184
	919	98.36356
	920	98.36529
	921	98.36701
	922	98.36872
	923	98.37043
	924	98.37214
	925	98.37385
	926	98.37555
	927	98.37725
	928	98.37894
	929	98.38063
	930	98.38232
	931	98.38401
	932	98.38569
	933	98.38737
	934	98.38904
	935	98.39071
	936	98.39238
	937	98.39405
	938	98.39571
	939	98.39737
	940	98.39902
	941	98.40067
	942	98.40232
	943	98.40396
	944	98.40561
	945	98.40724
	946	98.40888
	947	98.41051
	948	98.41214
	949	98.41376
	950	98.41539
	951	98.41241
	952	98.40944
	953	98.40648
	954	98.40354
	955	98.4006
	956	98.39768
	957	98.39477
	958	98.39187
	959	98.38898
	960	98.3861
	961	98.38323
	962	98.38037
	963	98.37752
	964	98.37469
	965	98.37186
	966	98.36904
	967	98.36624
	968	98.36345
	969	98.36066
	970	98.35789
	971	98.35513
	972	98.35238
	973	98.34964
	974	98.34691
	975	98.34419
	976	98.34148
	977	98.33879
	978	98.3361
	979	98.33342
	980	98.33075
	981	98.32809
	982	98.32545
	983	98.32281
	984	98.32018
	985	98.31756
	986	98.31495
	987	98.31235
	988	98.30977
	989	98.30719
	990	98.30462
	991	98.30206
	992	98.29951
	993	98.29697
	994	98.29444
	995	98.29192
	996	98.28941
	997	98.28691
	998	98.28442
	999	98.28193
	1000	98.27946
	1001	98.27847
	1002	98.27748
	1003	98.2765
	1004	98.27554
	1005	98.27457
	1006	98.27362
	1007	98.27268
	1008	98.27174
	1009	98.27081
	1010	98.26989
	1011	98.26897
	1012	98.26807
	1013	98.26717
	1014	98.26628
	1015	98.2654
	1016	98.26452
	1017	98.26366
	1018	98.2628
	1019	98.26194
	1020	98.2611
	1021	98.26026
	1022	98.25943
	1023	98.25861
	1024	98.2578
	1025	98.25699
	1026	98.25619
	1027	98.25539
	1028	98.25461
	1029	98.25383
	1030	98.25306
	1031	98.25229
	1032	98.25154
	1033	98.25078
	1034	98.25004
	1035	98.2493
	1036	98.24857
	1037	98.24785
	1038	98.24713
	1039	98.24642
	1040	98.24572
	1041	98.24502
	1042	98.24433
	1043	98.24365
	1044	98.24297
	1045	98.2423
	1046	98.24164
	1047	98.24098
	1048	98.24033
	1049	98.23969
	1050	98.23905

<2nd Example>
FIG. 2 is a schematic view of an electronic device 20 according to the 2nd example of the present disclosure. In FIG. 2, the electronic device 20 includes an imaging lens assembly module (its reference numeral is omitted) and an image sensor 280, wherein the image sensor 280 is disposed on an image surface (its reference numeral is omitted) of the imaging lens assembly module.
The imaging lens assembly module includes plastic light- folding elements 210, 230 and an optical imaging lens assembly (its reference numeral is omitted), wherein the plastic light-folding element 210 is disposed on an object side of the optical imaging lens assembly, and the plastic light-folding element 230 is disposed on an image side of the optical imaging lens assembly. In particular, the imaging lens assembly module can be applied to the telephoto (that is, the full view is less than 40 degrees) by the disposition of the plastic light- folding elements 210, 230. Therefore, the volume of the imaging lens assembly module can be effectively reduced.
The optical imaging lens assembly, in order from the object side to the image side, includes lens elements 221 a, 221 b, 221 c, 221 d and a retainer 223, and the lens elements 221 a, 221 b, 221 c are disposed in a lens barrel 222 of the optical imaging lens assembly, and the lens element 221 d and the retainer 223 are disposed in a driving member 224 of the optical imaging lens assembly, wherein the optical features such as numbers, structures, surface shapes and so on of the lens elements can be disposed according to different imaging demand, and the optical features are not limited thereto.
The plastic light-folding element 210 includes an incident surface 211, an exit surface 212, a reflective surface 213 and a reflective optical layer (its reference numeral is omitted), and the plastic light-folding element 230 includes an incident surface 231, an exit surface 232, a reflective surface 233 and a reflective optical layer (its reference numeral is omitted). In detail, the incident surfaces 211, 231 are configured to lead an imaging light (its reference numeral is omitted) enter the plastic light- folding elements 210, 230, respectively. The exit surfaces 212, 232 are configured to lead the imaging light exit the plastic light- folding elements 210, 230, respectively. The reflective surfaces 213, 233 are configured to fold the imaging light. The reflective optical layers are disposed on surfaces of the reflective surfaces 213, 233, respectively. According to the 2nd example, the plastic light-folding element 210 can be a plastic lens element, and each of the incident surface 211 and the exit surface 232 has an optical curved surface, but the present disclosure is not limited thereto.
Further, all of other structures and dispositions according to the 2nd example are the same as the structures and the dispositions according to the 1st example, and will not be described again herein.
<3rd Example>
FIG. 3A is a schematic view of an electronic device 30 according to the 3rd example of the present disclosure. In FIG. 3A, the electronic device 30 includes an imaging lens assembly module (its reference numeral is omitted) and an image sensor 380, wherein the image sensor 380 is disposed on an image surface 381 of the imaging lens assembly module.
The imaging lens assembly module includes a plastic light-folding element 310 and an optical imaging lens assembly 320, wherein the plastic light-folding element 310 is disposed an image side of the optical imaging lens assembly 320. In particular, the imaging lens assembly module can be applied to the telephoto (that is, the full view is less than 40 degrees). Therefore, the volume of the imaging lens assembly module can be effectively reduced.
FIG. 3B is a three dimensional view of the plastic light-folding element 310 according to the 3rd example in FIG. 3A. FIG. 3C is another three dimensional view of the plastic light-folding element 310 according to the 3rd example in FIG. 3A. FIG. 3D is a schematic view of an incident surface 311 and a reflective surface 313 of the plastic light-folding element 310 according to the 3rd example in FIG. 3A. In FIGS. 3A to 3D, the plastic light-folding element 310 includes the incident surface 311, an exit surface 312, the reflective surface 313, a reflective optical layer (its reference numeral is omitted), at least one connecting surface 315, at least one gate vestige structure 316 and at least one intermediate layer (its reference numeral is omitted). In detail, the incident surface 311 is configured to lead an imaging light (its reference numeral is omitted) enter the plastic light-folding element 310, the exit surface 312 is configured to lead the imaging light exit the plastic light-folding element 310, the reflective surface 313 is configured to fold the imaging light, and the reflective optical layer is disposed on a surface of the reflective surface 313, the connecting surface 315 is connected to the incident surface 311, the exit surface 312 and the reflective surface 313, and the gate vestige structure 316 is disposed on the connecting surface 315. According to the 3rd example, a number of the reflective surface 313 is four, a number of the connecting surface 315 is two, a number of the gate vestige structure 316 is two, a number of the intermediate layer is two, one of the reflective surfaces 313 and the incident surface 311 are coplanar, and another one of the reflective surfaces 313 and the exit surface 312 are coplanar, wherein the real number of the intermediate layer can be two or more, but the present disclosure is not limited thereto.
The reflective optical layer includes an Ag layer (its reference numeral is omitted), a bottom layer optical film (its reference numeral is omitted) and a top layer optical film (its reference numeral is omitted), wherein the Ag layer is configured to lead the imaging light, which enters the incident surface 311, reflect to the exit surface 312; the bottom layer optical film is directly contacted with the Ag layer, and the bottom layer optical film is closer to each of the reflective surfaces 313 of the plastic light-folding element 310 than the Ag layer to each of the reflective surfaces 313 of the plastic light-folding element 310; a refractive index of the top layer optical film is lower than a refractive index of the bottom layer optical film, wherein the top layer optical film is not directly contacted with the Ag layer, and the top layer optical film is farther from each of the reflective surfaces 313 of the plastic light-folding element 310 than the Ag layer from each of the reflective surfaces 313 of the plastic light-folding element 310.
According to the 3rd example, the bottom layer optical film is made of Al₂O₃, and the top layer optical film is made of SiO₂.
Furthermore, each of the incident surface 311, the exit surface 312 and the reflective surfaces 313 includes an optical portion (its reference numeral is omitted) and an arc step structure (its reference numeral is omitted), wherein the arc step structure is disposed on a periphery of the optical portion, and an arc is formed by the arc step structure centered on the optical portion.
When the refractive index of the bottom layer optical film is Nb, a thickness of the bottom layer optical film is db, the refractive index of the top layer optical film is Nt, a thickness of the top layer optical film is dt, a refractive index of the Ag layer is NAg, and a thickness of the Ag layer is dAg, the following conditions of the Table 3 are satisfied.

TABLE 3

3rd example

Nb	1.6726	db (nm)	20
Nt	1.4618	dt (nm)	65
NAg	0.051	dAg (nm)	100

It should be mentioned that the refractive index of the air is 1, the refractive index of the plastic light-folding element 310 is 1.64678, and a thickness of each of the intermediate layers is less than the thickness of the Ag layer.
Further, all of other structures and dispositions according to the 3rd example are the same as the structures and the dispositions according to the 1st example, and will not be described again herein.
<4th Example>
FIG. 4A is a schematic view of an electronic device 40 according to the 4th example of the present disclosure. FIG. 4B is another schematic view of the electronic device 40 according to the 4th example in FIG. 4A. In FIGS. 4A and 4B, the electronic device 40 according to the 4th example is a smart phone, and includes an imaging lens assembly module (its reference numeral is omitted), an image sensor (not shown) and a user interface 41, wherein the image sensor is disposed on an image surface (not shown) of the imaging lens assembly module, and the imaging lens assembly module includes an ultra-wide angle camera module 42, a high resolution camera module 43 and a telephoto camera module 44, and the user interface 41 is a touch screen, but the present disclosure is not limited thereto. Furthermore, the imaging lens assembly module includes a plastic light-folding element (not shown) and an optical imaging lens assembly (not shown), wherein the plastic light-folding element is disposed on one of an object side and an image side of the optical imaging lens assembly.
Moreover, the telephoto camera module 44 can be one of the imaging lens assembly modules according to the aforementioned 1st example to the 3rd example, but the present disclosure is not limited thereto. Therefore, it is favorable for satisfying the requirements of the mass production and the appearance of the imaging lens assembly module mounted on the electronic devices according to the current marketplace of the electronic device.
Moreover, users enter a shooting mode via the user interface 41, wherein the user interface 41 is configured to display the scene and have the touch function, and the shooting angle can be manually adjusted to switch the ultra-wide angle camera module 42, the high resolution camera module 43 and the telephoto camera module 44. At this moment, the imaging light is gathered on the image sensor via the imaging lens assembly module, and an electronic signal about an image is output to an image signal processor (ISP) 45.
In FIG. 4B, to meet a specification of the electronic device 40, the electronic device 40 can further include an optical anti-shake mechanism (not shown). Furthermore, the electronic device 40 can further include at least one focusing assisting module (its reference numeral is omitted) and at least one sensing element (not shown). The focusing assisting module can be a flash module 46 for compensating a color temperature, an infrared distance measurement component, a laser focus module and so on. The sensing element can have functions for sensing physical momentum and kinetic energy, such as an accelerator, a gyroscope, a Hall Effect Element, to sense shaking or jitters applied by hands of the users or external environments. Accordingly, the electronic device 40 equipped with an auto-focusing mechanism and the optical anti-shake mechanism can be enhanced to achieve the superior image quality. Furthermore, the electronic device 40 according to the present disclosure can have a capturing function with multiple modes, such as taking optimized selfies, high dynamic range (HDR) under a low light condition, 4K resolution recording and so on. Furthermore, the users can visually see a captured image of the camera through the user interface 41 and manually operate the view finding range on the user interface 41 to achieve the autofocus function of what you see is what you get.
Moreover, the imaging lens assembly module, the image sensor, the optical anti-shake mechanism, the sensing element and the focusing assisting module can be disposed on a flexible printed circuit board (FPC) (not shown) and electrically connected to the associated components, such as the imaging signal processor 45, via a connector (not shown) to perform a capturing process. Since the current electronic devices, such as smart phones, have a tendency of being compact, the way of firstly disposing the imaging lens assembly module and related components on the flexible printed circuit board and secondly integrating the circuit thereof into the main board of the electronic device via the connector can satisfy the requirements of the mechanical design and the circuit layout of the limited space inside the electronic device, and obtain more margins. The autofocus function of the imaging lens assembly module can also be controlled more flexibly via the touch screen of the electronic device. According to the 4th example, the electronic device 40 includes a plurality of sensing elements and a plurality of focusing assisting modules. The sensing elements and the focusing assisting modules are disposed on the flexible printed circuit board and at least one other flexible printed circuit board (not shown) and electrically connected to the associated components, such as the image signal processor 45, via corresponding connectors to perform the capturing process. In other examples (not shown herein), the sensing elements and the focusing assisting modules can also be disposed on the main board of the electronic device or carrier boards of other types according to requirements of the mechanical design and the circuit layout.
Furthermore, the electronic device 40 can further include, but not be limited to, a display, a control unit, a storage unit, a random access memory (RAM), a read-only memory (ROM), or the combination thereof.
FIG. 4C is a schematic view of an image according to the 4th example in FIG. 4A. In FIG. 4C, the larger range of the image can be captured via the ultra-wide angle camera module 42, and the ultra-wide angle camera module 42 has the function of accommodating more wide range of the scene.
FIG. 4D is another schematic view of an image according to the 4th example in FIG. 4A. In FIG. 4D, the image of the certain range with the high resolution can be captured via the high resolution camera module 43, and the high resolution camera module 43 has the function of the high resolution and the low deformation.
FIG. 4E is still another schematic view of an image according to the 4th example in FIG. 4A. In FIG. 4E, the telephoto camera module 44 has the enlarging function of the high magnification, and the distant image can be captured and enlarged with high magnification via the telephoto camera module 44.
In FIGS. 4C to 4E, the zooming function can be obtained via the electronic device 40, when the scene is captured via the imaging lens assembly module with different focal lengths cooperated with the function of image processing.
<5th Example>
FIG. 5 is a schematic view of an electronic device 50 according to the 5th example of the present disclosure. In FIG. 5, the electronic device 50 is a smart phone, and includes an imaging lens assembly module (its reference numeral is omitted) and an image sensor (not shown), wherein the image sensor is disposed on an image surface (not shown) of the imaging lens assembly module, and the imaging lens assembly module includes ultra-wide angle camera modules 511, 512, wide angle camera modules 513, 514, telephoto camera modules 515, 516, 517, 518 and a Time-Of-Flight (TOF) module 519. The TOF module 519 can be another type of the imaging apparatus, and the disposition is not limited thereto.
Moreover, the telephoto camera modules 515, 516, 517, 518 can be one of the imaging lens assembly modules according to the aforementioned 1st example to the 3rd example, but the present disclosure is not limited thereto. Therefore, it is favorable for satisfying the requirements of the mass production and the appearance of the imaging lens assembly module mounted on the electronic devices according to the current marketplace of the electronic device.
Further, the telephoto camera modules 517, 518 are configured to fold the light, but the present disclosure is not limited thereto.
To meet a specification of the electronic device 50, the electronic device 50 can further include an optical anti-shake mechanism (not shown). Furthermore, the electronic device 50 can further include at least one focusing assisting module (not shown) and at least one sensing element (not shown). The focusing assisting module can be a flash module 520 for compensating a color temperature, an infrared distance measurement component, a laser focus module and so on. The sensing element can have functions for sensing physical momentum and kinetic energy, such as an accelerator, a gyroscope, a Hall Effect Element, to sense shaking or jitters applied by hands of the users or external environments. Accordingly, the electronic device 50 equipped with an auto-focusing mechanism and the optical anti-shake mechanism can be enhanced to achieve the superior image quality. Furthermore, the electronic device 50 according to the present disclosure can have a capturing function with multiple modes, such as taking optimized selfies, High Dynamic Range (HDR) under a low light condition, 4K Resolution recording and so on.
Further, all of other structures and dispositions according to the 5th example are the same as the structures and the dispositions according to the 4th example, and will not be described again herein.
The foregoing description, for purpose of explanation, has been described with reference to specific examples. It is to be noted that Tables show different data of the different examples; however, the data of the different examples are obtained from experiments. The examples were chosen and described in order to best explain the principles of the disclosure and its practical applications, to thereby enable others skilled in the art to best utilize the disclosure and various examples with various modifications as are suited to the particular use contemplated. The examples depicted above and the appended drawings are exemplary and are not intended to be exhaustive or to limit the scope of the present disclosure to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings.

Claims

What is claimed is:

1. A plastic light-folding element, comprising:

an incident surface configured to lead an imaging light enter the plastic light-folding element;

an exit surface configured to lead the imaging light exit the plastic light-folding element;

a reflective surface configured to fold the imaging light; and

a reflective optical layer disposed on a surface of the reflective surface, and comprising:

an Ag layer configured to lead the imaging light, which enters the incident surface, reflect to the exit surface;

a bottom layer optical film directly contacted with the Ag layer, and the bottom layer optical film closer to the reflective surface of the plastic light-folding element than the Ag layer to the reflective surface of the plastic light-folding element; and

a top layer optical film, a refractive index of the top layer optical film lower than a refractive index of the bottom layer optical film, wherein the top layer optical film is not directly contacted with the Ag layer, and the top layer optical film is farther from the reflective surface of the plastic light-folding element than the Ag layer from the reflective surface of the plastic light-folding element;

wherein the refractive index of the bottom layer optical film is Nb, a thickness of the bottom layer optical film is db, the refractive index of the top layer optical film is Nt, a thickness of the top layer optical film is dt, a thickness of the Ag layer is dAg, and the following conditions are satisfied:

1.4<Nt<Nb<2.1;

1.6<Nb<2.1;

1.4<Nt<1.58;

0.05<db/dAg<1.2; and

0.2<dAg/dt<3.5.

2. The plastic light-folding element of claim 1, further comprising:

a connecting surface connected to the incident surface, the exit surface and the reflective surface; and

a gate vestige structure disposed on the connecting surface.

3. The plastic light-folding element of claim 2, wherein the bottom layer optical film is a metal oxide layer.

4. The plastic light-folding element of claim 2, further comprising:

at least one intermediate layer disposed between the top layer optical film and the Ag layer.

5. The plastic light-folding element of claim 4, wherein the at least one intermediate layer comprises a metal layer excluding a silver atom.

6. The plastic light-folding element of claim 2, wherein the thickness of the Ag layer is dAg, and the following condition is satisfied:

75 nm<dAg<200 nm.

7. The plastic light-folding element of claim 2, wherein the bottom layer optical film is directly contacted with the reflective surface of the plastic light-folding element.

8. The plastic light-folding element of claim 2, wherein the thickness of the bottom layer optical film is db, the thickness of the top layer optical film is dt, and the following condition is satisfied:

0.05<db/dt<1.1.

9. The plastic light-folding element of claim 2, wherein a lowest reflectivity of a reflectivity of the reflective optical layer between wavelengths of 540 nm to 590 nm is R5459, and the following condition is satisfied:

94.0%<R5459<99.99%.

10. An imaging lens assembly module, comprising:

the plastic light-folding element of claim 1; and

an optical imaging lens assembly, the plastic light-folding element disposed on one of an object side and an image side of the optical imaging lens assembly.

11. An electronic device, comprising:

the imaging lens assembly module of claim 10; and

an image sensor disposed on an image surface of the imaging lens assembly module.